Advancing Groundwater Management Strategies to Mitigate Land Subsidence

Groundwater extraction is a major driver of land subsidence, posing significant challenges in many regions. This study focuses on developing mitigation strategies through field experiments and numerical modeling, with severe subsidence areas in Taiwan selected as test sites for cyclic and reduced pumping trials. The analysis revealed a strong positive correlation between groundwater level changes and soil compression, as well as between groundwater level fluctuations and power consumption. Monitoring data from 24 wells indicated that groundwater extraction predominantly occurs during peak hours from 8:00 AM to 4:00 PM, while non-peak extraction spans 4:00 PM to 8:00 AM. Field experiments involving four wells under three scenarios—current conditions, cyclic pumping, and reduced pumping—demonstrated that cyclic pumping significantly reduced groundwater level drawdowns and soil compression compared to current practices. A three-dimensional numerical groundwater model was developed and calibrated to simulate these scenarios. Results showed that both cyclic and reduced pumping scenarios outperformed current conditions in minimizing drawdowns, with the optimal strategy being group-based cyclic pumping combined with a 50% reduction in extraction. These findings underscore the potential of targeted groundwater management practices in mitigating land subsidence effectively.